Synchronized beacon for wireless access point having multiple radios

ABSTRACT

A wireless access point having multiple radio transceivers and multiple antennas is operated by sending a beacon signal from several radio transceivers simultaneously. The radio transceivers may normally operate by delay sending a transmission when another ongoing transmission is detected, which would normally prevent beacon signals from being broadcast simultaneously. By forcing the beacon signals to transmit simultaneously, the available bandwidth is utilized much more efficiently. Embodiments include wireless access points that contain multiple directional antennas as well as those that have overlapping coverage areas.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority to and the benefit of U.S.Provisional Patent Application Ser. No. 60/594,315 entitled“Synchronized Beacon for Network Having Multiple Radios” filed on 28Mar. 2005 by Donald M. Bishop, the entire contents of which are herebyexpressly incorporated by reference.

BACKGROUND OF THE INVENTION

a. Field of the Invention

The present invention pertains generally to communication networks andspecifically to networks having multiple radios.

b. Description of the Background

Wireless communications networks are being widely deployed. In order toensure subscriber coverage, a wireless network may have several radiotransceivers positioned so that the coverage areas of the radiosoverlap. As radio coverage areas overlap, some interference andundesirable cross-communication between radios may occur. Suchinterference may decrease available bandwidth, which diminishes thenumber and quality of potential subscriber connections.

Many wireless protocols have a feature whereby a device can sense ifanother device is using the specific frequency or band, and the firstdevice will refrain from transmitting. In some protocols, the firstdevice may retry the transmission at a later time, which may be arandomly generated time. Such a feature aims to minimize one device‘talking over’ another device and preventing both device's transmissionsfrom getting through. This collision detection feature is widely used inmany different protocols, including standard wired Ethernet and wirelessEthernet-based protocols such as IEEE 802.11 wireless protocols.

A distinct problem with such protocols is that the bandwidth isinherently underutilized and throughput for each device can be much lessthan optimal, especially when many devices are communicating on thenetwork. When many devices attempt to communicate on the bandsimultaneously, the collision detection and avoidance procedures beginto occupy much of the communication bandwidth.

It would therefore be advantageous to provide a system and method forproviding improved use of the available bandwidth for communicationnetworks having several radios.

SUMMARY OF THE INVENTION

A wireless access point having multiple radio transceivers and multipleantennas is operated by sending a beacon signal from several radiotransceivers simultaneously. The radio transceivers may normally operateby delay sending a transmission when another ongoing transmission isdetected, which would normally prevent beacon signals from beingbroadcast simultaneously. By forcing the beacon signals to transmitsimultaneously, the available bandwidth is utilized much moreefficiently. Embodiments include wireless access points that containmultiple directional antennas as well as those that have overlappingcoverage areas.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings,

FIG. 1 is a diagrammatic illustration of an embodiment showing awireless network with overlapping coverage areas.

FIG. 2 is a diagrammatic illustration of an embodiment showing awireless access point having multiple radios.

FIG. 3 is a flowchart illustration of an embodiment showing a method forsynchronizing beacon signals for networked radios.

FIG. 4 is a plan view illustration of a residential neighborhood havingwireless access service.

DETAILED DESCRIPTION OF THE INVENTION

While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof are shown by way ofexample in the drawings and will herein be described in detail. Itshould be understood, however, that there is no intent to limit theinvention to the particular forms disclosed, but on the contrary, theinvention is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the invention as defined by theclaims. Like reference numbers signify the elements throughout thedescription of the figures. It will also be understood that when anelement is referred to as being “connected” or “coupled” to anotherelement, it can be directly connected or coupled to the other element orone or a multitude of intervening elements may also be present. Incontrast, when an element is referred to as being “directly connected”or “directly coupled” to another element, there are no interveningelements present.

The present invention may be embodied as devices, systems, methods,and/or computer program products. Accordingly, the present invention maybe embodied in hardware and/or in software (including firmware, residentsoftware, micro-code, etc.) Furthermore, the present invention may takethe form of a computer program product on a computer-usable orcomputer-readable storage medium having computer-usable orcomputer-readable program code embodied in the medium for use by or inconnection with an instruction execution system. In the context of thisdocument, a computer-usable or computer-readable medium may be anymedium that can contain, store, communicate, propagate, or transport theprogram for use by or in connection with the instruction executionsystem, apparatus, or device.

The computer-usable or computer-readable medium may be, for example butnot limited to, an electronic, magnetic, optical, electromagnetic,infrared, or semiconductor system, apparatus, device, or propagationmedium. More specific examples (a non-exhaustive list) of thecomputer-readable medium would include the following: an electricalconnection having one or more wires, a portable computer diskette, arandom access memory (RAM), an erasable programmable read-only memory(EPROM or Flash memory), an optical fiber, a portable compact disc readonly memory (CD-ROM), and a digital versatile disk read only memory(DVD-ROM). Note that the computer-usable or computer-readable mediumcould even be paper or another suitable medium upon which the program isprinted, as the program can be electronically captured, via, forinstance, optical scanning of the paper or other medium, then compiled,interpreted, of otherwise processed in a suitable manner, if necessary,and then stored in a computer memory.

FIG. 1 illustrates an embodiment 100 showing a wireless network withoverlapping coverage areas. A network controller 102 is connected to anetwork backbone 104. Connected to the backbone 104 are radiotransceivers 106, 108, 110, and 112. Each radio transceiver has anantenna, such as antenna 109 connected to transceiver 108. Transceiver106 has a coverage area 114. Similarly, transceivers 108, 110, and 112have coverage areas 116, 118, and 120, respectively. A wireless device122 is located in an overlapping coverage area 124. In the area 124,radio transmissions from transceivers 106, 108, and 112 all overlap.

In embodiment 100, two or more of the transceivers 106, 108, 110, and112 may simultaneously transmit a beacon signal. By simultaneouslytransmitting a beacon signal, bandwidth is freed up that would otherwisebe dedicated to transmitting and receiving beacon signals fromtransceivers with overlapping coverage areas.

Radio transceivers 106, 108, 110, and 112 may periodically transmit abeacon signal. Such a signal may identify the transceiver and provideinformation such that other devices in the area may begincommunications. In many embodiments, the beacon signal may provide aunique identifier for the radio, as well as an identifier for thenetwork and transmission parameters so that another device maysuccessfully initiate communications.

In many cases, radios that communicate with digitized or other forms ofdata communication, in a similar way as human operated audio radiocommunication, are able to listen on the communication band, determinethat the band is quiet, then begin a transmission. If another device istransmitting, the radio is able to wait until the band is quiet beforeattempting another transmission. This technique prevents two radios fromsimultaneously transmitting and distorting each other's signals.

Many standards have been developed for automated data transmission overwireless airwaves. Examples are cellular phone networks, wireless datastandards such as EEE 802.11, various spread spectrum and time divisionmultiple access standards, and many others.

As more devices are attempting to communicate in a certain geographicalarea, the available bandwidth decreases. Especially after a certainnumber of devices is reached, the available bandwidth and datathroughput decreases exponentially as more devices are added.

One reason for the decrease in bandwidth is the communications overheadassociated with each device. For example, fixed base stations maytransmit a beacon signal on a periodic basis. In a typical prior artapplication, when one radio transmits a beacon signal, another radiowithin the area would be thereby forced to wait to transmit its beaconsignal or any other signal. In an area where many radio coverage areasoverlap, a significant portion of the bandwidth might become clutteredwith the repeated transmission of beacon signals of the transceiversfrom overlapping coverage areas. This is because as each radio transmitsits own beacon signal, all other devices typically refrain fromtransmitting.

In the embodiment 100, two or more of the transceivers maysimultaneously transmit beacon signals. The coordinated transmission ofbeacon signals may eliminate much of the transmission overhead on achannel or frequency that is shared by all the transceivers. Thecoordination and synchronization of the beacon signals may beaccomplished using many methods. In one method, a centralized controller102 may transmit various signals along a network backbone 104 to causethe various transceivers to synchronize.

In some embodiments, every transceiver having overlapping coverage areawith another transceiver may transmit synchronized beacon signals,whereas in other embodiments two or more transceivers may do so. Inparticularly busy areas, synchronized beacon signals are especiallyuseful, since the bandwidth can be at a premium in congested areas.

Some radio transmission schemes have a base and remote architecture. Insuch a scheme, the base stations have a defined transmission scheme thatmay include a repeated beacon signal. The remote devices in such ascheme may or may not transmit a beacon signal and may or may not beable to communicate directly from one remote device to another. Examplesof such schemes include IEEE 802.11 and the various cellular phonearchitectures. In many cases, the base stations are connection pointsfor other networks such as the Internet or POTS phone system.

In contrast, other schemes have a peer to peer architecture. In such ascheme, each device operates in the same manner as all the other devicesin the area and any device is able to transmit to any other device inthe area.

One purpose of a beacon signal is to alert other devices in the area ofa station's presence. In situations where a remote device is in the areaof a base station, the remote device may be capable of listening for abase station's beacon signal, interpreting the signal, and establishingconnections.

For example, the device 122 is located within the transmission coverageareas of radio transceivers 106, 108, and 112. The area 124 ishighlighted showing the overlapping coverage areas. If the beaconsignals of the transceivers 106, 108, and 112 were asynchronouslytransmitting beacon signals, each transceiver 106, 108, and 112 wouldwait until the other transceivers had completed their beacon signalsbefore transmitting a beacon signal of its own. This process would takeup at least three times the bandwidth of a single beacon signal. In someinstances, since some devices may delay more than others after detectingthat another device was transmitting, the bandwidth used up by thebeacon signals may be four or more times the bandwidth consumed by asingle beacon signal.

When the transceivers 106, 108, and 112 simultaneously transmit a beaconsignal, the device 122 may be able to detect and decode at least one ofthe beacon signals. In practice, it is likely that the device 122 maydetect and decode the beacon signal from the nearest transceiver. Inthis example, the device 122 may be able to detect and decode the beaconsignal from transceiver 108 because the signal to noise ratio for thebeacon signal from transceiver 108 may be greater than either of thesimultaneous beacon signals from transceivers 106 and 112. In somesituations, the device 122 may detect the beacon signals from one of thetransceivers 106 or 112, depending on the relative signal strength ofthe particular beacon signal.

Overlapping coverage areas are typical of many wireless networks where afull coverage is desired over a specific area. For example, a wirelessdata network may provide coverage in a large building, shopping mall, orairport using multiple radio transceivers with overlapping coverageareas. Similarly, a school campus or residential neighborhood may beblanketed by various wireless networks for data, voice, or othercommunications.

Beacon signals from one or more radio transceivers may be synchronizedby sending a synchronizing signal over the network 104 that connects thetransceivers. In many cases, a controller 102 may provide a repeatedsynchronizing signal known as a heartbeat. In some cases, the heartbeatmay be transmitted for every occurrence of a beacon signal. In othercases, the heartbeat may be transmitted once to coordinate a clock oneach of the radio transmitters. In such cases, the synchronized clocksin the radio transmitters may continue to repeatedly transmitting beaconsignals based on an internal oscillator in the radio.

For the purposes of this specification, the terms “radio,” “radiotransceiver,” “wireless access point,” “transceiver,” and similar termsare used interchangeably. Similarly, the terms “backbone,” “network,”“network backbone,” etc. are also used interchangeably.

Many network architectures comprise a network backbone with severalwireless transceivers attached to the backbone. For example, a wirelessservice provider may connect several wireless access points usingdigital subscriber line (DSL) connections to a central access point. Inanother example, a cable television and internet connection service maybe provided through a hybrid fiber/coax (HFC) network with wirelesssubscriber connections mounted on utility poles or utility pedestals ina neighborhood.

The network backbone 104 may be any type of hardwired or wirelessconnection between the various transceivers. In some configurations, thebackbone 104 may be fiber optic cable, coaxial cable, twisted pair, orsome other directly connected communication path. In otherconfigurations, microwave communications or other radio frequency may beused to connect various portions of the network. In still otherconfigurations, any combination of connection may be used.

The controller 102 may be any type of device in communication with oneor more of the transceivers. In some configurations, the controller 102may be a centralized computer, hub, switch, gateway, headend, CableModem Termination System (CMTS), Digital Subscriber Line AccessMultiplexer (DSLAM), or any other device that communicates along thebackbone 104. In some configurations, the controller 102 may provideconnection between the backbone 104 and the Internet, telephone network,or another outside network.

In some configurations, the controller 102 may be a dedicated devicethat provides a synchronization function for the transceivers. In stillother configurations, one of the transceivers may have a controllerfunction enabled and function as both a transceiver as well as thecontroller 102.

The controller 102 may provide various sorts of communications in orderto synchronize the beacon signals of the various transceivers attachedto the backbone 104. For example, the controller 102 may send out a‘heartbeat’ or synchronization pulse that can be used by thetransceivers to synchronize the beacon signals. In anotherconfiguration, the controller 102 may transmit a single transmissionthat is used to synchronize an oscillator on each transceiver.Thereafter, the oscillator within each transceiver will indicate when abeacon signal is to be sent. In some cases, the synchronization signalmay be sent from the controller 102 periodically to resynchronize theoscillators in the transceivers.

FIG. 2 illustrates an embodiment 200 of a wireless access point havingtwo radio transceivers. The wireless access point 202 contains radiotransceivers 204 and 206. Directional antennas 207 and 208 are connectedto transceivers 204 and 206, respectively. A networkinterface/controller 210 connects the transceivers to the network 214.An optional beacon heartbeat generator 212 is located inside thewireless access point 202. Another optional beacon heartbeat generator216 may be connected to the network 214. The directional antenna 207 hasa coverage area 218. Similarly, the directional antenna 208 has acoverage area 220. The overlapping coverage area 222 is the area whereboth antenna signals overlap.

The wireless access point 202 may be a single device that is fixedlymounted in an area for wireless communications. For example, thewireless access point 202 may be mounted in an airport terminal, acoffee shop, a residential neighborhood, an office building, or anyother area where it is desired to service the area with two or moreradio transceivers. In many cases, a single radio transceiver may beoverwhelmed by the communications, so it may be desirable to service thearea by using multiple radios with directional antennas to coverspecific sectors. In some cases, the sectors may overlap, while in othercases the sectors may not overlap.

In some configurations, the proximity of the antennas 207 and 208 maycause some interference between the two radio systems. In such cases, itis possible that the beacon signal from one antenna may be received bythe other antenna, causing the receiving transceiver to become quietwhile the other transceiver is transmitting.

The beacon signals of the two radio transceivers 204 and 206 may besynchronized by a beacon heartbeat generator 212 that is part of thewireless access point 202. The beacon heartbeat generator 212 may be anoscillator that generates a pulse at a predetermined interval. The pulsemay be communicated to the radio transceivers 204 and 206 and indicatethat a beacon signal is to be transmitted. In some configurations, theheartbeat generator 212 may send a signal for each beacon signal, whilein other configurations, the heartbeat generator 212 may send a singlesignal, or may send a signal at other intervals. The network beaconheartbeat generator 216 may function in the same manner as the built-inbeacon heartbeat generator 212, but may be located remotely.

In many configurations, the radio transceivers 204 and 206 may beindependent devices having separate processors and capable of operatingindependently from each other. Such a configuration may allow eachtransceiver 204 or 206 to conduct separate communications with deviceswithin its coverage area. Each transceiver 204 and 206 may have adedicated input line or be otherwise adapted to receive a beacontransmission signal from the controller 210 or beacon heartbeatgenerators 212 or 216.

The network interface/controller 210 may perform several functions,including transmitting communications between the network 214 and theradio transceivers 204 and 206. In some configurations, the networkinterface/controller 210 may have a processor or state machine that isindependent from the radio transceivers 204 and 206.

The embodiment 200 illustrates an example of a multiple radiotransceiver system where the radio transceivers are located in veryclose proximity. Some configurations may have three or more radiotransceivers. In some configurations, the system may have the wirelessaccess point 202 located in one location, with the directional antennas207 and 208 located remotely. For example, a wireless access point 202may be located on one floor of a multistory building while the variousdirectional antennas may be each located on a different floor of thebuilding. The directional antennas in such an example may have ahorizontal coverage area that covers one floor of the building.

The embodiment 200 functions in a similar manner as the embodiment 100,with multiple radios having a synchronized beacon signal. In the case ofembodiment 200, the ‘backbone’ may be a communication path through thecontroller 210.

In a specific configuration of embodiment 200, a wireless access point202 may be mounted in a single box with the directional antennas 207 and208 mounted on the outside surface of the box. Such a configuration maybe mounted on an interior wall of a building, whereas a weather tightconfiguration may be mounted on a utility pole, utility pedestal, or onan exterior wall of a building.

FIG. 3 illustrates an embodiment 300 of a method for synchronizingbeacon signals for networked radios. The process begins in block 302.For each wireless access point in block 304, a calibration packet ormessage is sent along the network in block 306 and returned in block308. The transmission delay for the wireless access point is calculatedin block 310. The maximum transmission delay is determined in block 312.For each wireless access point in block 314, a beacon delay iscalculated in block 316 by subtracting the transmission delay for thatwireless access point from the maximum delay determined in block 312.The beacon delay is stored in block 318. The network heartbeat is begunin block 320. Each wireless access point transmits a beacon signal usingits particular beacon delay after receiving the heartbeat in block 322.Block 322 is repeated.

Embodiment 300 is one method by which a group of networked radios may besynchronized. Such a method is applicable to a configuration such asembodiment 100 where various radios are dispersed along a communicationbackbone. The method 300 takes into account the propagation delay of thecommunications backbone so that the beacon signals of all the radios aretransmitted substantially simultaneously. In some configurations, eachwireless access point may contain one radio transceiver, while in otherconfigurations, one or more wireless access points may contain multipleradios as illustrated in embodiment 200.

In very few cases will the beacon signals of the synchronized radios bebroadcast exactly at the same instant. However, the beacon signals maybe broadcast substantially simultaneously such that most of the radiosare broadcasting a beacon signal substantially at the same time. In manycases, the start and end of the beacon signals may not be exactlysimultaneous, but in general the beacon signals may overlap in time.

In the embodiment 300, a transmission delay is calculated for eachwireless access point in blocks 306, 308, and 310. The transmissiondelay may be the transmission time from the heartbeat generator to theparticular wireless access point. Many transmission networks havemechanisms for determining a transmission delay. For example, many cabletelevision plants have methods for determining transmission delay. Anymethod for transmission delay calculation may be used while keepingwithin the spirit and intent of the present invention.

After the transmission delay is determined for each wireless accesspoint, a beacon delay is calculated for each wireless access point bysubtracting the transmission delay from the maximum transmission delayof all the wireless access points. When a heartbeat signal is received,each wireless access point may delay the beacon signal by its beacondelay so that all of the radios may broadcast a beacon signal atsubstantially the same time.

In some configurations, the beacon delay calculated in block 316 may bestored in a memory location of the wireless access point in block 318.In other configurations, the beacon delay may be stored in a centralizedcontroller. In such a configuration, the controller may transmitseparate signals to each of the radios to synchronously broadcast thebeacon signal. The controller may use the beacon delay of each wirelessaccess point to determine the exact time that a beacon transmit signalis to be sent to a particular wireless access point.

When the beacon delay is stored in the wireless access point, thecontroller may transmit a single communication to all of the radios.When the signal is received by the wireless access point, the wirelessaccess point may delay the broadcast of the beacon signal by the beaconsignal delay. In this manner, all of the radio transceivers maybroadcast the beacon signal substantially simultaneously.

In some configurations, the heartbeat may be transmitted at each beaconsignal, whereas in other configurations, the heartbeat may betransmitted once and oscillators within each radio may be used todetermine when a beacon signal is to be rebroadcast.

FIG. 4 illustrates a plan view of an embodiment 400 showing wirelessaccess points deployed in a residential area. A road 402 is shown withseveral houses 404. Wireless access points 406, 408, and 410 are shownwith their respective coverage areas 412, 414, and 416 that blanket theresidential complex. The network backbone 418 runs along the main road402 and has a junction 420 that connects the wireless access points 406,408, and 410 along the branch line.

Embodiment 400 is an application for wireless connectivity in aresidential area. The wireless access points 406, 408, and 410 mayprovide various communications to and from the homes 404, such asinternet data connections, voice telephony, video services, and anyother communication. In many applications, the wireless access pointsmay use a standardized radio communications protocol, such as thosedefined by IEEE 802.11 specification. In other applications, differentradio communications protocols, including custom or non-standardprotocols, may be used.

The wireless access points 406, 408, and 410 may be mounted on utilitypoles for areas that have overhead utility lines. In areas withunderground utilities, the wireless access points may be mounted onutility pedestals that are short stanchions connected to the undergroundcabling. The utility pedestals may also may be used for making variousconnections with the underground cabling.

The network backbone 418 may be a coaxial cable, fiber optic, twistedpair, or other communications cable. In some configurations, the networkbackbone 418 may be similar to a conventional cable television plantusing DOCSIS or other communication protocols. In other configurations,the network backbone 418 may be twisted pair DSL lines that areconnected using a DSLAM. In still other configurations, the network maybe an Ethernet or Ethenet-type network.

The wireless access points 406, 408, and 410 may be configured such thatthe beacon signals from all of the wireless access points are broadcastsubstantially simultaneously. The coordination and synchronization ofthe beacon signal may be performed by various methods, including themethod described in embodiment 300 and variations of such method.

The foregoing description of the invention has been presented forpurposes of illustration and description. It is not intended to beexhaustive or to limit the invention to the precise form disclosed, andother modifications and variations may be possible in light of the aboveteachings. The embodiment was chosen and described in order to bestexplain the principles of the invention and its practical application tothereby enable others skilled in the art to best utilize the inventionin various embodiments and various modifications as are suited to theparticular use contemplated. It is intended that the appended claims beconstrued to include other alternative embodiments of the inventionexcept insofar as limited by the prior art.

1. A wireless access point comprising: a connection to a network; a plurality of antennas; a plurality of radio transceivers, each of said plurality of radio transceivers being adapted to establish at least one two-way data communication session, and adapted to delay sending a transmission when another ongoing transmission is detected; wherein each of said plurality of radio transceivers being adapted to transmit a beacon signal substantially simultaneously.
 2. The wireless access point of claim 1 further comprising: a controller adapted to send a synchronization signal to said plurality of radio transceivers substantially simultaneously.
 3. The wireless access point of claim I wherein at least one of said plurality of antennas is a directional antenna.
 4. The wireless access point of claim 1 wherein said antennas are arranged such that a first portion of a first coverage area of a first of said plurality of radio transceivers overlaps a second portion of a second coverage area of a second of said plurality of radio transceivers.
 5. The wireless access point of claim 1 wherein at least one of said plurality of radio transceivers is adapted to substantially operate in conformance to IEEE 802.11 specification.
 6. The wireless access point of claim 1 wherein a first of said plurality of radio transceivers is adapted to sense said beacon signal transmitted by a second of said plurality of radio transceivers and adjust the transmission of said beacon signal sent by said first of said plurality of radio transceivers so that said beacon signals are transmitted substantially simultaneously.
 7. The wireless access point of claim 1 wherein said beacon signal comprises an identifier for a radio transmitter.
 8. The wireless access point of claim 1 wherein said beacon signal comprises a network identifier.
 9. The wireless access point of claim 1 wherein at least one of said radio transceivers are mounted on a utility pole.
 10. The wireless access point of claim 1 wherein at least one of said radio transceivers are mounted in a utility pedestal.
 11. The wireless access point of claim 1 wherein said network further comprises an Internet connection.
 12. The wireless access point of claim 1 wherein said network comprises coaxial cable.
 13. The wireless access point of claim 1 wherein said network comprises fiber optic cable.
 14. The wireless access point of claim 1 wherein said network comprises a hybrid fiber/coax connection.
 15. The wireless access point of claim 1 wherein said network comprises a radio communication path.
 16. The wireless access point of claim 1 wherein at least one of said plurality of radio transceivers is adapted to operate in substantial conformance with IEEE 802.11 specification.
 17. The wireless access point of claim 1 wherein said beacon signal comprises an identifier for a radio transmitter.
 18. The wireless access point of claim 1 wherein said beacon signal comprises a network identifier.
 19. A method comprising: establishing communications between a controller and a plurality of radio transceivers comprising a wireless access point, said wireless access point being connected on a network, said radio transceivers being adapted to establish at least one two-way data communication session, and adapted to delay sending a transmission when another ongoing transmission is detected; sending a synchronization signal from said controller to said plurality of radio transceivers; and transmitting a beacon signal from each of said plurality of radio transceivers substantially simultaneously using said synchronization signal.
 20. The method of claim 19 wherein said controller comprises a connection to the Internet.
 21. The method of claim 19 wherein at least one of said radio transceivers comprises a directional antenna.
 22. The method of claim 21 wherein a portion of a first coverage area of one of said plurality of radio transceivers overlaps a portion of a second coverage area of a second of said plurality of radio transceivers.
 23. The method of claim 19 wherein said controller is remotely located on a network.
 24. The method of claim 19 wherein said controller is integral to said wireless access point. 